You may ignore this warning if you prefer to use root to ssh into server and frequently use this. If you would like to secure your server more and use unprivileged user for ssh, you will need to create a user via shell and make him a member of the wheel group so that it could do su to root. Then you can disable root logins via ssh by setting PermitRootLogin to no in /etc/ssh/sshd_config. SSH demon restart will be required after that (service sshd restart). Please bear in mind that if you do not create a user and do not make it the wheel group member, you will lose root access via ssh to the server.
I hope this helps.